Apparatus for introducing air to insulated electrode structures in electrical precipitators



Oct. 24, 1950 F. H. VlETS 2,526,715

- APPARATUS FOR mmonucmc AIR T0 INSULATED ELECTRODE STRUCTURES IN ELECTRICAL PRECIPITATORS Filed Oct. 25, 1947 :5 Sheets-Sheet 1 IN VEN TOR.

w aw M Oct. 24, 1950 Filed Oct. 25. 1947 F. H. VIETS APPARATUS FOR INTRODUCING AIR T0 INSULATED ELECTRODE STRUCTURES IN ELECTRICAL PRECIPITATORS 3 Sheets-Sheet 2 INVENTOR.

f I t/9 1% m 7 TI'OBNEV Oct. 24, 1950 F. H. VIETS 2,526,715

APPARATUS FOR INTRODUCING AIR T0 INSULATED ELECTRODE STRUCTURES IN ELECTRICAL P EcIRITAToRs Filed Oct. 25, 1947 3 Sheets-Sheet 5 IN V EN TOR.

@ mqv Patented Oct. 24, 1950 UNITED T TE "OFFICE APPARATUS FOR "INTRODUCING AIR T-O IN .SULATED .ELECTRODE STRUCTURES IN ELECTRICAL PRECIPITATORS Floyd H. Viets; Glendale, Calif.',assig' n0i' to West-' ern 'Trecipita'tion'*Gorporation, Los- Angeles,

Calif., a corporation of California Application October 25, 1947, Serial No, 782,076?

niiderthe influenceoi an electric field,' toward a collecting electrode. Whfen the collected material isaldrysolid, it ordinarily accumulates upon the surface .of the collecting electrode, and 'itibecomes necessaryto clean the electrode periodically infl order tomaintain the efliciency of the precipitator.v Under these circumstances, cleaning an electrode .can .be accomplished by delivering ,a'

series of sharp blows to the electrode to jar or shakeloose theaccumulated material which,'.of its .own weight, then .falls downwardly to s'ome point beneath theelectrode. I '1 "'lil heflbulk of the suspended material ordinarily accumulates upon the grounded collect n gelectrode, and there is no problemof grounding the electrodeinvolved in cleaning it; The hammeror other meansTQr jarringfthe conect ng electrode is commonly operated'by compressed ,air;,- and since ,the collecting electrode is grounded ,to the precipitator shell, a metallicflconduit for compressed air may be used leading to the hammer means.

1 It is quite common -f,or.,a considerable of the material suspended in the gas streainto be deposited upon the high tension electrode, and it 11 Claims.

portion 7 is in cleaning this electrode that the problem particularly, arises of operating a suitable hammer or'shaki'ng mechanism without grounding the high tension electrode. Various types of automatic operating mechanisms" for. electrode .rappershavebeen devised, and certain of them require compressed air. In the case of a rapping mechanism of this type, when applied to a high tension electrode; there is a problem of conductingjthe compressed air through'the precipitator shell to therapper while at the sameetime maintaining the high tension electrode insulated from ground and from'the other low tension portions of the precipitator shell.

Because my invention has been. designed and adapted to the solution of this problem inconnectio'nwith the operation of rappers for high tension electrodes, 'ILshow my invention in this particularfembodiment. However, it will be under stoodthat my invention is not necessarily limited to this application, but may housed in connection with anyotherfltype of mechanism operated or actuated by air pressure which must be kept insulatedel'ectrically. r

Thus itlbecomes a general object of vmy invention to provide means'for leading a' fluid supply line to afiuid-pressure actuated rapper mounted upon 'a high tension i electro'de Without grounding the electrode and without connecting that electrodeelectricallyito thejs'hell or other similar portion or'the precipitator.

jIItIis also an. object or .my invention to provide? means for conducting a supplylo'f compressed. air or thfelike to afluid-pressiire actuated rapper or similar device in an electrical precipitator, without relyingupoii conduit sections made from rubber or ,otherlinsulating materials which are subject .to, "'terioration under high temperatures es. above and other objects of my invention are,attainedjbyproviding, in connection with 'a fluid-pressure'actuated rapping or similar device on'a liigh tension electrode, fluid supply means f0 "theirapper'which comprises a lead-in which inc desianinsulator member or section engaging jifo fides'member'orpart oi the shell." In one iorm of invention the lead-in may comprisea suspensionimeinber,for supporting and electrically insulatingthe electrode assembly from the shell. "The. lead-in has a fiuidpassage extending throughl'itcand communicatingat one end with theinteriorrofa grounded housing which encloses that end ofthe lead-inor suspension member.

The ,grounded housingiis connected to means ,for supplyin .gasleouS fluid under pressure to the housingiinterior, the' fluid then flowing through i the passage within the lead-in to a conduit 1 at the otherjend whi'chis connected withthe rapping device. f

l low .Qthe above objects and advantages of my inv'j'en ionf'as wellas others not specifically menti d;herein,ar e'attained will be more readily app re tj byreference to the following descriptionano t'otheannexedgdrawings, inwhich: p

' Eig'. is a fragmentaryvertical section through "t V felectri ca l' precipitator looking in the tion of gas flowyshowingthehigh tension and 'collecting electrode assemblies with arappingjjdevice,attachedflto the hi'ghtension assemlolly,.andnieansfoii-supplying fluid under pressure to'the rapper,"

sngupp xposu e'ro acid or other chemical Fig. 2 is a fragmentary vertical section through the upper end of the high tension electrode assembly on line 22 of Fig. 1, showing the rapping device in side elevation;

Fig. 3 is an enlarged vertical section on line 33 of Fig. 1 through the top end of an insulator for the high tension electrode assembly showing the filter mounted at the upper end of the insulator;

Fig. 4 is an enlarged fragmentary elevation and section taken on line 44 of Fig. 1 showing the lower end of the electrode assembly suspension member, the fluid passage therein, and the connection with the conduit leading to the rapping device; and

Fig. 5 is a fragmentary vertical section through an electrical precipitator showing a modified form of my invention.

In order to illustrate and disclose my invention, Fig. 1 shows a portion of an electrical precipitator which is typical of industrial precipitators for collecting dry solids suspended in a stream of gas. Because the details of construction and arrangement of the various parts of an electrical precipitator are, in general, well known to persons skilled in the art and are not a part of the present invention, description of such details will be limited here to a disclosure of those necessary to understand how my invention may be applied or adapted to a typical precipitator construction. It will be understood that my invention is in no way limited to the particular precipitator construction shown herein, nor to any one particular type of fluid-pressure actuated rapping means for the electrodes; but the invention may be applied equally well to other precipitators and to various types of rappers. Modifications in the locations and connections between the several parts are within the scope of persons skilled in the art.

The electrical precipitator in Fig. l is contained within a housing or shell l0 which not only encloses the electrode assembly but also provides a duct through whichthe dust-laden gas stream flows. The direction of gas flow is perpendicular to the plane of the drawing. The structural framework of the precipitator includes posts l4 within shell Hi which support at their upper ends transverse beam if) at the top of the gas duct. From two such beams l5, spaced in the direction of gas flow, are suspended a plurality of plates |6 which extend parallel to the direction of gas flow. Plates it constitute individual collecting electrodes. The collecting electrode assembly, including plates i6 and beams l5, are all connected together, both electrically and mechanically, and are connected to shell in. Since shell I0 is grounded electrically, all these parts are also grounded through the shell.

The high tension electrode assembly comprises a pair of transverse members, of which only the upper channel member I8 is shown. The lower member is similar to the one illustrated and is positioned directly beneath it. The upper and lower transverse members |8 are connected by a pair of vertically extending members I9, here from each pipe 20 is a plurality of rod or wire elements 22 which are the discharge electrodes.

Each of the rectangular end frames of the high tension electrode assembly just described, is suspended by two hanger rods or tubes 24 which are attached at their lower ends to upright members l9 and extend upwardly through sleeves 25 into insulators 26. At least certain ones of hangers 24 are hollow in order to provide for a fluid supply passage, as will be explained in greater detail. Otherwise, the members 24 may be solid rods. Each hanger 24 is secured at its upper end to a metal cap 28 which rests upon the top of an insulator 26, as shown in detail in Fig. 3. Each insulator 26 has an enlarged portion which rests upon a flange provided by housing 21, in order to support the insulator. The joint between insulator 26 and the flange of housing 21 is made fluid-tight, and for this purpose a gasket or other means between the insulator and housing flange may be employed. This fluid-tight connection not only keeps the gases being treated from escaping upwardly through housing 21, as in the case of the right-hand insulator in Fig. 1, but also prevents compressed air from entering the gas duct, as in the case of the left-hand insulator in Fig. 1.

The device for rapping the electrode assembly is indicated generally at 30, and is rigidly attached to the under side of a top transverse member l8 by its upper flange 3|. It has been found by experience that this is a particularly effective point at which to deliver the rapping blows. However, the rapping device may be attached to any other member of the electrode assembly, and more than one rapper for each assembly may be used, if desired. The rapping device comprises two housing portions 32 and 33 which are boiled together and provide a cylinder within which a piston, indicated at 3'! in Fig. 2, is movable under air pressure. Exhaust ports (not shown) in the cylinder are covered by a shield 34 to prevent entry of foreign matter into the cylinder. The details of the internal construction of the rapping device 30' are not shown in this application. Reference may be had to my co-pending application Ser. No. 715,020, filed December 9, 1946, on Pneumatic Method and Apparatus for Rapping Electrodes in Electrical Precipitators, for detailed information regarding the construction and operation of this particular type of rapping device.

shown as angles, thus forming a generally rectangular end frame. Two such end frames, spaced apart in the direction of gas flow, support between them a plurality of pipes 20, or other similar longitudinally extending members. As may be seen best in Fig. 2, pipes 20 are attached to transverse beams l8 by lJ-bolts 2|, or other similar means. Pipes 23 extend in the direction of gas flow, and are parallel to and midway between two collecting electrodes |6. Suspended Gaseous fluid under pressure is supplied to rapping device 30 by fluid supply means which includes a length of flexible metal hose 35 attached to a fitting on lower body portion 33 by an elbow 36, and also pipe 33 which is connected to the other end of hose 35. Pipe 38 is held in place by brackets 39 bolted to angle 40 which is attached to one face of channel l8. Pipe 38 is connected to pipe 4| by elbows 42 and 43 and an intervening nipple. Pipe 4| is located within, and extends vertically for the full length of one of the hollow suspension members 24 for the electrode assembly.

Pipe 4| is fastened at its upper end to plug 45 which is welded or otherwise secured in place within the upper end of suspension member 24. Plug 45 eifects a fluid-tight closure of the interior of member 24 to prevent the passage of fluids into or out of the precipitator shell through this hollow member. Cap member 48 is screwed onto the upper end of pipe 4|, as shown in Fig. 3, and is provided with a pair of small passages 50 which provide communication between the interior of pipe 4| and the exteriorof cap 48.

In the operation of the particular rapping desmegma myi-co-pending application referredi'to above, it;

is desirable that! theretbe one or. more .small. ori;

ficesinthefluid supply means in order to effect a degree of control over the-fiow of air through the supply means. For thispurpose orifices 50 areprovided; but it will beunderstood that itiis within the scope of my invention to eliminate cap 48 and orifices 5i) entirely, as the fiuid supply means might just as well be used to' supply fluid to -some other type of -mechanism in which the flow control afforded by these orifices is unnecessary. Itis desirable to surround orifices50'with a suitable filter, such as wire cloth sereen SI, inorder to remove from thefiuid'any solid particles which might lodge in passages 5!] and interfere with-the fiow therethrough of fluid.

The fiuidsupply means also includes air line 52 and bell housing 53 which covers or encloses the upper end' of insulator 25 and is secured tothe to'p of housing 27 in sucha manner as to effect a fiuid -tight joint therewith. Bell housing 53 being connected electrically to housing 2 1, the former is electrically grounded by this connection to shell l0. Pipe 4|, cap 48, and filter 5| are connected; electrically to the high tension electrode-assembly through hanger rod 24, and are consequently maintained at relatively high potential. For this reason, housing 53 must be everywhere sufficiently spaced f-rom filter 5| that no spark-over can occur between the housing and filter 5| or any other'nearbyhigh tension parts.

-Air line 52' is connectedto any suitable source of compressed air, or other gaseous fluid under,

pressure-which is adapted to use by some mechani'sm within the precipitatonsuch as tank 54 in which air is stored by a compressor unit, not shown. It may be desirable, although not neces-. sary, to attach several lines 52 to a single tank 54-by means of .a distribution valve ormanifold D. Fluid. under pressure is conducted from tank 54, or other suitable source, 'byline 52 into hell housing 53 which forms a part of the means su-piplying fluid under pressure. Housing 53 encloses and defines a spaced-filled by fiuid under pressure and surrounding the upper ends of insulator 26 and fluid supply pipe 4|. The walls of the housing are sufficiently spaced from these parts that there is no danger of grounding or short-circuiting the high tension elements through this fluid body. The interior of pipe 4| communicates with the space inside housing 53, in this particular instance through orifices 50 and ca'p':48, and air under pressure'fiows from the interior of the housing down through. pipe 4|, pipe 38; and hose 53, to rapping device30.

It is within the scope of my invention to eliminate pipe 4| as a separate member, and use the wall of tube 24' to define the fiuid supply passage. In this way, the electrode assembly suspension member and fluid passage means are combined into asingle element. However, it is preferable to utilize the construction shown in the drawings since the weight of the electrode assembly'is ordinarily so great that a pipe of small diametensuch as tube 4|, is not sufiicientlystrong to carry the imposedload; .and on the other hand a large diameter member suchas tube 24 may supply the compressed air at a greater rate than plus :various minor parts. As an example of how this lead-.inassembly can be simplified, referenced may be had to Fig; 5 in'which is shown a varia;

tionaluform of. my invention which diifers 'frofii therfo'regoing chiefiyxin' tworespects. In the first place, theleadr-in of 5 performs. no supporting functiomsince it carries no weight except its own; .and in. the second place the rapper is not mounted directly'on the. electrode, but it is maintainedlat a high potential since it is connected electricallyrto the high tensionelectrode.

:I-nithisform of the invention, a housing 5'! is mounted upon .precipitator shell in and has Within. it a fluid-pressure operated vibrator or rapper 60. Rapper 60 is mounted on the upper end of rod 6| which passes downwardly through sleeve 62 supported upon disc-type insulator 63. The lower end of rod 6| is constrained to verticalrm'ovement by guide 64 which is mounted by channel 65 on the top of transverse electrode member l8. Without going into the details of operation, it is sufficient to say that vibrator 60, upon receiving compressed air, causes rod 6| to move up and down rapidly, striking a series of sharpblows against plate 66 on channel 65. The vibration travels through channels 65 to channel |8, thus jarring the electrode assembly so that the accumulated deposits fall off. Channels 65 may be attached tomore than one transverse channel l8.

At the upper end of housing 51 is, a hollow elongated insulator68 mounted near its midpoint on plate 69 in such a fashion that the insulator and plate make a fluid-tight joint with the'top-wall of housing 51. Also on top of housing 5?, is mounted bell housing 10, the joint between the two housings being fluid-tight so that the -interior of housing H3 is adapted to .hold fiuid under pressure. Apart of the top wall of housing 5? is'common to housing 10 and may be considered a part of the latter in order to make of housingxlflha. complete enclosure able to contain compressed air inside. Fluid is supplied under pressure to the interior of housing 10 through, line 52.

The upper end of insulator 68 extends into and communicates with the interior of housing 10 so that fluid under pressure may flow from the interior of the housing into and through fiuid passage means in the form of pipe H which extends. longitudinally for the full length of insulator 6B. The lower end of pipe H is connected by-a.-length=of flexible metallic hose T2 to vibrator to supply fluid under :pressure to the vibrator.

..In.order to effect a fluid-tight seal-between the insulator and tube H, the tube is threaded into nuts -14-and mat the upper and lower ends respectively of the insulator. Suitable gaskets are provided underneath these nuts --to obtain the necessary seal with the insulator. Housing H! is of sufiiciently large diameter that no spark-over can occur-to nut 14 or other high tension part.

.Aszin the form of my invention previously described; itwill be appreciated that housing 51 and 1.0 are-electrically grounded through their connection to shell :0. The lead-in for conducting the supply of fluid into the shell consists of insulator 68, and tube the latter being at high potential because of its, electrical connectionjto the high. tension electrode assembly and its insulation from the'lowtension or grounded portions of the precipitatorbymeans of insulator 68. Insulator 68 carries little or'noload, except itsown weight; and performs no suspension function relative to the electrodes. It is preferred thatthe fiuidpassage through the insulator be formed by pipe 1| inlorder that fluid-tight connections can easily be made; but itwill be understoodthat it is with in 'the scope of'my invention to have'the fluid mam 7 passage formed by the body of the insulator itself and omit pipe H, except as a similar pipe is connected to one end of the insulator.

Having disclosed a preferred form of my invention, it will be apparent that various changes in construction and arrangement of parts may be made by persons skilled in the art without departing from the spirit and scope of my invention; and consequently I wish it understood that the foregoing description is considered as being illustrative of, rather than limitative upon, the appended claims.

I claim:

1. In an electrical precipitator, fluid supply means for introducing gaseous fluid under pressure into the precipitator shell, comprising: a grounded housing defining a space adapted to contain fluid under pressure; an insulator extending into said space and provided with fluid passage means for conducting fluid under pressure from said space; and a conduit at high potential connected to and receiving fluid from said passage means.

2. In an electrical precipitator, fluid supply means for introducing gaseous fluid under pressure into the precipitator shell, comprising: a housing maintained at low potential and enclosing a space adapted to contain fluid under pressure; electrically conductive fluid passage means electrically connected to an electrode at high potential, and communicatin with the body of fluid in said housing to receive fluid under pressure therefrom; and insulator means engaging the housing and surrounding the fluid passage means where it enters the housing to electrically insulate the passage means from the housing.

3. In an electrical precipitator as in claim 2, the combination including a fluid-pressure actuated rapper operatively engaging the electrode at high potential and supplied with fluid under pressure by said fluid passage means.

4. In an electrical precipitator having a high tension electrode within a grounded shell and a fluid-pressure actuated device on the electrode, means for supplying gaseous fluid under pressure to the device, comprising: a vertically elongated high tension electrode suspension member in contact with a grounded member and having a longitudinally extending fluid passage therein; a fluid-tight grounded housing enclosing the upper end of the suspension member and defining an interior space containing fluid under pressure and communicating with said fluid passage; means for supplying fluid under pressure to the housing interior; and conduit means connecting the fluid passage to the device.

5. In an electrical precipitator having a high tension electrode within a grounded shell and a fluid-pressure actuated rapping device on the electrode, means for supplying gaseous fluid under pressure to the rapping device, comprising: a vertically elongated high tension electrode suspension member in contact with a grounded member and having a longitudinally extending fluid passage therein; a fluid-tight grounded housing enclosing the upper end of the suspension member and defining an interior space containing fluid under pressure and communicating with said fluid passage; means for supplying fluid under pressure to the housing interior; and conduit means connecting the fluid passage to the rapping device.

6. In an electrical precipitator having a high tension electrode assembly within a grounded shell, the combination comprising: a cylinder rigidly attached to a member of the electrode assembly and containing a fluid-pressure actuated. piston; and means for supplying gaseous fluid un der pressure to the cylinder to actuate the piston, said means comprising a high tension electrode in, a grounded housing enclosing one end of the suspension member and communicating with the fluid passage therein, means for supplying fluidv under pressure to the interior of said;housing,; and a conduit connecting the fluid passage with the cylinder.

7. In an electrical precipitator having a high tension electrode assembly within a grounded shell and a fluid-pressure actuated device for rap-- ping the electrode assembly, means for supplying gaseous fluid under pressure to the device, comprising: a grounded fluid-tight housing enclosing a space adapted to receive and contain gaseous fluid under pressure; an insulator extending through one wall of the housing and provided with fluid passage means communicating with said space to receive gaseous fluid therefrom; and a conduit connected to said insulator and insulated thereby from said wall, communicating with said fluid passage means and connected to the fluid-pressure actuated device for conducting gaseous fluid to said device.

8. In an electrical precipitator having a high tension electrode assembly within a grounded shell and a fluid-pressure actuated device for rapping the assembly, means for supplying gaseous fluid under pressure to the device, comprising: a grounded fluid-tight housing having a wall sepa-; rating the interior thereof from the shell interior; inlet means for supplying gaseous fluid under pressure to said space; an insulator connected to said wall and provided with fluid passage means communicating with said space to receive gaseous fluid therefrom; and a conduit connected to said insulator and communicating with said fluid passage means and extending into the shell for conducting fluid to said device.

9. In an electrical precipitator, the combination comprising: a grounded shell for enclosing a stream of dust-laden gas to be treated; a fluidtight housing supported by the shell and electrically connected thereto, the housing being adapted to contain a gaseous fluid under pressure; fluid inlet means connected to a housing Wall for introducing gaseous fluid under pressure into saidhousing; and a high tension insulator extending from inside the housing through a housing wall, and having fluid passage means therein for conducting fluid under pressure out of said housing.

10. In an electrical precipitator, the combination comprising: a grounded shell enclosing astream of dust-ladengas to be treated; a fluid-- tight housing having one wall separating the shell interior from the housing interior, the housing being adapted to contain gaseous fluid under pressure; means for supplying fluid under pressure to the housing; and an electrical insulator passing through said one wall and having internal passage means for conducing fluid under pressure out of the housing to the shell interior.

11. In an electrical precipitator, the combination comprising: a grounded shell enclosing a' stream of dust-laden gas to be treated; a'fluidtight housing having one wall separating the shell interior from the housing interior, the housing being adaptedto contain a gaseous fluid under pressure; means for supplying fluid under pressure to the housing; an electrical insulator passing REFERENCES CITED tmwgh Sam one and an electrode Suspen' The following references are of record in the slon member bearing on top of the insulator and me of this patent.

extending through the insulator, the suspension 7 member having fluid passage means for conduct- 5 FOREIGN PATENTS ing fluid under pressure out of the housing. Number c ntr Date 406,451 Germany Nov. 26, 1924 FLOYD H. VIETS. 490,163 Germany Jan. 27, 1930 

